Tokyo-based Toppan Printing, who works in collaboration with electronic paper display maker E-Ink, has demonstrated a stunning 400ppi (pixels per inch) high resolution e-paper prototype. Toppan has also manufactured the highly acclaimed 170ppi display of Sony's e-book reader LIBRIé.

Speaking of display resolution: High resolution is as good as the human eye can resolve. Going beyond it would be pointless because the average human eye could not appreciate any finer detail. In a monochromatic image at a normal reading distance, the human eye is not able to perceive more than 250-300ppi. In other words, the 400ppi display prototype easily matches the resolving power of the eye making text as sharp as it can get!

Beside featuring a high resolution, in contrast to traditional display technologies on the market today, E-Ink's e-paper technology also makes text extremely easy to read at virtually any angle and under any lighting condition - including direct sunlight.

Isn't it strange that the Librie is the only handheld device so far that features E-Ink technology? So far most news on E-Ink was related to large screen applications such as screens used for advertisement.

I begin to wonder if the Librie was only meant as a test product to see how consumers accept the new technology (remember it also has its disadvantages, such as a very slow refresh-rate, low-scale grey colors).

Isn't it strange that the Librie is the only handheld device so far that features E-Ink technology? So far most news on E-Ink was related to large screen applications such as screens used for advertisement.

I begin to wonder if the Librie was only meant as a test product to see how consumers accept the new technology (remember it also has its disadvantages, such as a very slow refresh-rate, low-scale grey colors).

I think there are several reasons for this. First off, I am sure Sony has a deal with E-Ink giving them exclusive distribution for some time. In this time, they will try hard to succeed with their DRM approach - if they pull it off, it would mean more money in the long run. Only if the device fails due to DRM they'll wake up and give the customers what they want.
Secondly, yes, the display has its limitations. Not only is it very slow, there's also a problem with ghosting - if you change pages whatever was on the previous page remains visible as a slight shadow. It's annoying if you pay attention to it, but it doesn't really interfere with reading.